Since I use this same PC machine since 10 years, something has changed, as we solved this before (would need to scan old github bugs to see how, but we basically installed non-free packages default, which could have changed or seem missing, IF this is a packaging thing and not something misconfigured as described in link above even though we dont use GNOME)
while we have non free repos defined in sources, the wifi adpater is missing
looking under etc/network as suggested in post#4 seems to show no interfaces at all: https://forums.debian.net/viewtopic.php?t=157101
Since I use this same PC machine since 10 years, something has changed, as we solved this before (would need to scan old github bugs to see how, but we basically installed non-free packages default, which could have changed or seem missing, IF this is a packaging thing and not something misconfigured as described in link above even though we dont use GNOME)